package br.com.caelum.vraptor.panettone;
import static java.nio.file.Files.isDirectory;
import static java.nio.file.LinkOption.NOFOLLOW_LINKS;
import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
import java.io.IOException;
import java.io.PrintStream;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
public class Watcher implements Runnable {
private final WatchService service;
private boolean running = true;
private final Compiler compiler;
private final Map<WatchKey,Path> keys = new HashMap<>();
private boolean trace = false;
private final PrintStream out = System.out;
private final PrintStream err = System.err;
Watcher(Path folder, Compiler compiler) {
this.compiler = compiler;
try {
this.service = FileSystems.getDefault().newWatchService();
registerAll(folder);
} catch (IOException e) {
throw new RuntimeException(e);
}
trace = true;
}
private void registerAll(final Path start) {
try {
Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
register(dir);
return FileVisitResult.CONTINUE;
}
});
} catch (IOException e) {
throw new RuntimeException(e);
}
}
private void register(Path dir) throws IOException {
WatchKey key = dir.register(service, ENTRY_CREATE,
ENTRY_MODIFY,
ENTRY_DELETE);
if (trace) {
Path prev = keys.get(key);
if (prev == null) {
out.format("Registering new path: %s\n", dir);
} else if (!dir.equals(prev)) {
out.format("update: %s -> %s\n", prev, dir);
}
}
keys.put(key, dir);
}
@SuppressWarnings("unchecked")
@Override
public void run() {
while (running) {
WatchKey key = getKey();
if (key == null)
continue;
Path dir = keys.get(key);
if (dir == null) {
err.println("WatchKey not recognized: " + key);
continue;
}
List<WatchEvent<?>> events = key.pollEvents();
boolean shouldDelete = events.stream()
.map(WatchEvent::kind)
.anyMatch(ENTRY_DELETE::equals);
events.stream()
.map(e -> (WatchEvent<Path>) e)
.peek(e -> out.println("> " + dir.resolve(e.context()).getFileName()))
.filter(e -> e.kind()==ENTRY_CREATE)
.map(e -> e.context())
.map(name -> dir.resolve(name))
.filter(path -> isDirectory(path, NOFOLLOW_LINKS))
.forEach(this::registerAll);
if(shouldDelete) compiler.clear();
compiler.compileAll();
key.reset();
}
}
private WatchKey getKey() {
try {
return service.poll(30, TimeUnit.SECONDS);
} catch (InterruptedException e) {
return null;
}
}
void stop() {
try {
this.running = false;
out.println("Stopping compilation service");
service.close();
out.println("Stopped compilation service");
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}